10. August 2022

Air Zermatt has patent on new fire-fighting boiler

Air Zermatt has patented a fire-fighting boiler that improves fire-fighting with helicopters while increasing pilot safety. Another advantage: since one tonne of extinguishing water can be concentrated and dropped on the source of the fire within only three seconds, the extinguishing effect is higher compared to previous boilers. The fire-fighting boiler was developed by Air Zermatt founder Beat Perren.

Some extinguishing systems used so far have had their pitfalls. With the often used "Bambi Bucket", extinguishing water cannot be dropped fast enough over the source of the fire. Therefore, a large part of the extinguishing water evaporates before it reaches the source of the fire. Furthermore, with an empty "Bambi Bucket" there is a danger that the extinguishing bag will blow up during the rapid descent into the tail rotor. These disadvantages prompted Air Zermatt founder Beat Perren to work on a new fire-fighting boiler. This has now been patented.

One tonne of extinguishing water in three seconds

The new, pneumatic aluminium extinguishing tank can be filled with either 1000 or 800 litres of extinguishing water. At our altitudes, this corresponds to the carrying capacity of both the Ecureuil H125 (AS 350 B3) and the twin-engine Bell 429 helicopters, which can be used for night operations. A tonne of extinguishing water can be dropped over the source of the fire in just three seconds. At the push of a button, the pilot can open the bottom of the tank. The extinguishing water thus reaches the source of the fire in a concentrated way. 

To achieve maximum extinguishing effect in firefighting, the extinguishing water must not only be concentrated, but also discharged as close as possible above the fire. If the extinguishing water is discharged high above the source of the fire, it hits the fire in droplet form as rain. This reduces the extinguishing effect because part of the extinguishing water evaporates uselessly even before it hits the source of the fire due to the high temperatures. The patented Air Zermatt fire-fighting boiler makes it possible to drop the extinguishing water close to the source of the fire compared to the means used so far. The boiler is suspended from the helicopter's load latch with steel cables that can be extended as required. This allows the pilot to fly above the heat and smoke and still drop the extinguishing water close above the source of the fire.

The clock is ticking 

In the event of a fire, helicopters must be called out as quickly as possible. This is why, for example, the motto in the canton of Valais is: Smoke in the forest - helicopter! The time factor plays a decisive role in firefighting. Helicopter companies widely use the so-called "Bambi Bucket" for firefighting - an extinguishing bag that can be carried in the helicopter and thus enables a faster overflight speed. For the short distances in Switzerland, this advantage is of no consequence compared to the Air Zermatt fire-fighting boiler.

With the empty "Bambi Bucket", the pilot has to reduce the airspeed considerably during descent so that the empty plastic container does not blow up at the back and damage the helicopter's tail rotor. This is what happened to an army Super Puma when extinguishing the large forest fire in Visp. The empty Air Zermatt fire-fighting boiler flies smoothly even in a fast descent. Not only can the kettle be filled in a water basin much faster than the previously used extinguishing bags, it can also be filled directly with a fire hose in only about 25 seconds. The new Air Zermatt fire-fighting boiler thus saves valuable time during filling, emptying and also during the return flight.

Innovative from the beginning

In the more than 50-year history of the Valais helicopter company, Air Zermatt has not only made a name for itself internationally in alpine air rescue through its pioneering work (first drop attempts by mountain guides on the notorious Eiger North Face in 1970, first direct rescue on the Eiger North Face in 1971), since the beginning of the 1070s Air Zermatt has also done a lot of development work in forest firefighting with helicopters. Two years after its foundation, a large-scale forest fire broke out in the Thelwald forest in the municipality of Raron. At the time, Air Zermatt was only able to help with the transport of firefighters and fire-fighting equipment. This experience prompted Air Zermatt to look for possibilities to intervene directly in the fire-fighting operation with helicopters. Air Zermatt developed the tipping extinguishing tank, in which the pilot flings the extinguishing water into the fire at a speed of 60 to 80 km/h while flying forward.

In order to achieve a successful extinguishing effect in forest fires, water drops must be made at the shortest possible intervals. Therefore, the water supply point should be as close as possible to the source of the fire. However, this is rarely the case, because a sufficiently deep standing or running body of water with a depth of at least 1.50 m is required to fill the fire-fighting boilers. At the end of the 1970s, Air Zermatt had a mobile water basin made with a capacity of 44,000 litres, which is placed near the fire to minimise the helicopter's rotation time.  The water basin straightens itself up when filled with water. The dimensions of the Air Zermatt basin were chosen so that the fire-fighting boilers in it could be filled quickly. The Air Zermatt water basin has been used in almost all forest fires and has proven its worth.

Air Zermatt, Firefighting, Helicopter

The new, patented fire-fighting boiler from Air Zermatt

Air Zermatt, Firefighting, Helicopter

Air Zermatt founder Beat Perren | © Dominic Steinmann

Air Zermatt, Firefighting, Helicopter

One ton of extinguishing water in 3 seconds


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